1. Field of the Invention
This invention relates to an image processing apparatus and, more particularly, to an image processing apparatus capable of outputting reversed colors using Y (yellow), M (magenta), C (cyan) and K (black) colorants. The invention relates also to a method of reversing color in this image processing apparatus.
2. Description of the Related Art
In a black-and-white binary printing apparatus in which a black-white reversal command is provided, a bit map within a designated range is reversed when the reversal command is received, whereby a black-white reversal is performed.
In a case where a black-white reversal is applied to a multicolor printing apparatus, such as a Y (yellow)-, M (magenta)- and C (cyan)-three-color printing apparatus, as shown in FIG. 2, Y, M and C bit maps are as illustrated in (a) through (c) of FIG. 2, where the characters Y, M, C and K represent yellow, magenta, cyan and black, respectively. The Y, M and C bit maps following a simple reversal become as shown in (d) through (f) of FIG. 2, and the outputted result is depicted in (g) of FIG. 2. More specifically, merely by reversing each bit map, Y.fwdarw.M+C (blue), M.fwdarw.Y +C (green), C.fwdarw.Y+M (red), K.fwdarw.white, and background .fwdarw.Y+M+C (black) are obtained, and a color reversal based upon complementary colors is substantially achieved.
However, when the above-described black-white reversal is applied, for example, to a YMCK four-color printing apparatus as shown in FIG. 3, merely reversing the Y, M, C and K-bit maps shown in (a) through (d) of FIG. 3 to provide the reversals of (e) through (h) of FIG. 3 and the output (i) of FIG. 3 results in Y.fwdarw.M+C+K (black), M.fwdarw.Y+C+K (black), C.fwdarw.Y+M+K (black), K.fwdarw.Y+M+C (black), and background.fwdarw.Y+M+C+K (black). Thus, a drawback is that all of the maps become pure black.